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Note that this study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.

Video capsule endoscopy was superior to ileocolonoscopy for diagnosing Crohn's disease among patients with spondyloarthritis.

Note that the study looked at various serologic, inflammatory, and genetic biomarkers that might act as screening tests, and found that the fecal calprotectin test had a sensitivity of 74% and a specificity of 87%, with a positive test being defined as ≥100 μg/g.

Among 64 patients with spondyloarthropathy, significant inflammation of the bowel was detected in 45% with video capsule endoscopy compared with only 14% using ileocolonoscopy (P=0.036), according to Ernest G. Seidman, MD, of McGill University in Montreal.

There are several forms of spondyloarthritis, including reactive arthritis, psoriatic arthritis, and arthritis associated with uveitis, but the prototypical variant is ankylosing spondylitis. Patients tend to be HLA-B27 positive but are seronegative, lacking rheumatoid factor, he explained.

Textbooks of rheumatology typically state that between 5% and 10% of patients with ankylosing spondylitis have coexisting inflammatory bowel disease, but that greatly underestimates the prevalence of the gastrointestinal disorder, he said.

"So how often does Crohn's disease coexist with spondyloarthritis and ankylosing spondylitis? We know they appear in the same families. But only about 6% have clinically apparent symptoms of inflammatory bowel disease, and even if they are symptomatic it's possible that their symptoms could be related to [Nonsteroidal anti-inflammatory drugs] use or irritable bowel syndrome," Seidman commented.

"Some limited studies using protocol ileocolonoscopy have shown a much higher prevalence than the 5% to 10%, but most rheumatologists don't consult gastroenterologists for protocol ileocolonoscopies in these patients, and the patients aren't generally in favor of it," he said.

Therefore, to see if video capsule endoscopy might aid in the diagnosis of coexisting Crohn's disease in patients with spondyloarthropathy, he and his colleagues have been enrolling patients prospectively in a study known as SpACE Capsule.

Patients with spondyloarthritis with or without gastrointestinal symptoms were eligible for the study. They had to be off NSAIDs for at least 4 weeks, and could not have been exposed to tumor necrosis factor (TNF) inhibitors other than etanercept (Enbrel), which does not influence Crohn's disease outcomes.

Patients were put on a liquid diet, and the capsule endoscopy was done the next day prior to the colonoscopy. Capsule results were assessed blindly using the Lewis score, with the minimum score for a positive test of inflammation being set at 350.

Among the 64 patients who have thus far completed the study, 58% had symptoms and all but three were HLA-B27 positive. Four cases had been treated with etanercept.

Aside from the head-to-head comparison of detection rates with the capsule endoscopy and ileocolonoscopy, Seidman and colleagues also looked at various serologic, inflammatory, and genetic biomarkers that might act as screening tests, and found that the fecal calprotectin test had a sensitivity of 74% and a specificity of 87%, with a positive test being defined as ≥100 μg/g.

"This was very promising, with an area under the curve of 0.75, so we feel that in the hands of a rheumatologist who's interested in referring a patient to us for assessment of possible or probable Crohn's disease, the fecal calprotectin test would be a good screening test provided the patient is not on NSAIDs because that can interfere with the results," he said.

No correlation with Crohn's disease was seen for C-reactive protein, and while NOD2 mutations were higher in patients with Crohn's disease (27% versus 11%), this was not statistically significant (P=0.22).

"What's very important for us to consider is that in 65% of patients, the detection of small bowel Crohn's disease led to a change in treatment, from a therapy that the rheumatologist may have been using to treat the spondyloarthritis to an anti-TNF agent that can cover both the rheumatologic condition and Crohn's disease," he said.

A follow-up study is investigating mucosal healing after treatment, "and after the first dozen patients we really have quite astounding improvements in mucosal healing, which really for the most part in the [inflammatory bowel disease] world has relied on colonoscopy. There hasn't been much done with mucosal healing looking at the small bowel," he said.

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